U.S. Pat. No. 3,616,177 discloses a laminar composite comprising a polyimide layer having FEP, which is copolymer of tetrafluoroethylene (TFE) and hexafluoropropylene (HFP), coated on one or both sides and having a polytetrafluoroethylene (PTFE) polymer exterior surface layer.
U.S. Pat. No. 4,628,003 discloses a heat-sealable, high-temperature laminate composite comprising a polyimide interior layer between fluoropolymer layers, where the fluoropolymer layers have from 1 to 20 weight percent of a finely divided inorganic pigment material.
U.S. Pat. No. 5,238,748 discloses an insulation wrap having a polyimide layer and one or more layers comprising a blend of PTFE and fluorinated copolymer.